Assisting device for unfolding a motor vehicle inflatable airbag

ABSTRACT

An assisting device for unfolding an inflatable airbag, located at the junction of at least two fitting elements of a motor vehicle body parts. The first of the two fitting elements is fixed and the second of the two fitting elements is configured to be deformed under the pressure exerted by the inflatable airbag when it moves. A guiding surface of an outlet zone of the inflatable airbag is oriented towards an end portion of the second fitting element and is located at the outer limit of a co-operating zone between the first and second fitting elements.

The invention relates to a device for assisting the deployment of amotor vehicle airbag, and more particularly to an airbag located at thejunction of two trim elements.

In order to protect the passengers during a side-impact collision thereare used inflatable cushions commonly known as airbags. In response to ahigh-energy impact, these airbags inflate between the passenger and theside of the passenger compartment of a motor vehicle.

As described in European Patent A 0791511, one solution for integratingthe airbag in view of its deployment is to fix it under the roof trimand more particularly at the limit of the said trim. The airbag is thenpositioned between the side window and the head of the passenger to beprotected during its deployment, the border of the roof trim beingdeformed in order to permit passage of the said airbag.

Such deployment can be made difficult when the airbag forms a protectivecurtain covering the interior side parts of the vehicle. The airbag inthe form of a curtain deploys not only at the level of the window partsbut also at the level of the center-pillar and rear side-panel trimsthat form a junction with the roof trim. The junctions of the trims thencreate an obstacle that can interfere with deployment of the airbag.

Since the time of deployment of the airbag must be as short as possible,any obstacle that can lengthen this time may have serious consequencesfor the efficacy of the protective device.

In order to alleviate these disadvantages, one object of the inventionis a device that ensures guidance of the airbag during its deployment.

Another object of the invention is a very low-cost guide deviceintegrated into the trims or other parts of the motor vehicle.

According to one characteristic of the invention, it is provided with aguide surface oriented from an exit zone of the said airbag toward anend part of the second trim element, which abuts against the said guidesurface and is located at the outer limit of the zone of cooperationbetween the first and second trim elements.

According to another characteristic of the invention, the guide surfaceis part of one of the trim elements.

According to another characteristic of the invention, the junction ofthe guide surface with the trim element forms a lip for holding thefirst and second trim elements in closed position relative to oneanother.

According to another characteristic of the invention, the guide surfaceis a support element of the airbag.

According to another characteristic of the invention, the guide surfaceis part of a body element.

According to another characteristic of the invention, the guide surfacecarries an element for fixation of the first trim element.

Other characteristics and advantages of the invention will become clearon reading the description of practical examples of a device forassisting the deployment of an airbag with reference to the attacheddrawings, wherein:

FIG. 1 illustrates a section through a side part of the vehicle providedwith the device according to the invention for assisting the deploymentof an airbag.

FIG. 2 illustrates another embodiment of the invention.

In the description that follows, the practical example will relate toonly one side of the passenger compartment. It is self-evident that thispractical example can be used on both sides of the passenger compartmentof the motor vehicle. In addition, the practical example will relate toapplication to the rear side-panel and center-pillar trims, although itcan be easily adapted to any other type of trim. The invention can alsobe used for any airbag other than one of the curtain type, whosedeployment can be improved by using the device according to theinvention.

As illustrated in FIG. 1, the motor vehicle is provided with bodyelements, and in particular with a passenger compartment 1 and a roof 2.These body elements are provided with interior trims, designed amongother things to ensure a degree of sound insulation and above all toimpart a pleasing appearance.

The side of the passenger compartment is provided, in its rear part inparticular, with a rear side-panel trim and, in its center part, at thejunction of the front and rear doors, with a center-pillar trim.

The roof is provided with a trim that extends over its entire surfaceand, via these side limits, is joined to the rear side-panel andcenter-pillar trims.

In our practical example, the roof trim covers an airbag device 3 whichextends from front to rear of the vehicle, above the side doors. In itsnon-deployed state, airbag 3 is located substantially at the level ofthe junction of the roof trim and of the center-pillar and rearside-panel trims. The roof trim is provided with an end 21 that can bemoved under the pressure exerted by the deployment of airbag 3, thuspermitting the said airbag to exit rear part 4 of the trim and becomeinterposed between the passenger and the side part of the motor vehicle.In our practical example, the rear side-panel and center-pillar trimsare fixed.

To facilitate understanding of the description of the practicalexamples, the fixed trim elements, such as the rear side-panel andcenter-pillar trims, will be designated as first trim element 10, whilethe trim provided with a movable part 21, such as the roof trim, will bedesignated as second trim element 20. It is self-evident that first andsecond trim elements 10 and 20 can each comprise a plurality ofelements.

At the level of the junction with second trim element 20, first trimelement 10 is provided with a holding lip 11 for border 22 of secondtrim element 20. Close to lip 11, first trim element 10 is also providedwith a guide surface 12 for the deployment of airbag 3, having a forminclined toward the junction of the said first and second trim elements10 and 20. Guide surface 12 can be molded in one piece with first trimelement 10. Holding lip 11 is then formed partly by the junction ofguide surface 12 with first trim element 10.

The inclination of guide surface 12 is oriented from exit zone 5 of thesaid airbag 3 toward an end part 23 of second trim element 20, locatedat the outer limit of the zone of cooperation between first and secondtrim elements 10 and 20, in such a way as to direct airbag 3, during itsdeployment, toward movable end 21 of second trim element 20. In FIGS. 1and 2, the outer limit corresponds substantially to the intersection ofarrow F with movable part 21.

In addition, as illustrated in FIG. 2, and in order to facilitatefixation of first trim element 10 and to improve its stability duringdeployment of airbag 3, upper part 13 of guide surface 12 can beprovided with fixation tabs 14 or with a catch molded directly to thetrim element, which tabs cooperate with apertures made in the bodyelements or with catches 6 positioned on the said body. The fixation oftrim 10 is then achieved by inserting tabs 14 or the catch into theapertures, thus making it possible to achieve better holding, especiallyin the upper part of the said trim 10.

During its deployment, airbag 3 is braced against guide surface 12,which directs the development of the said airbag 3 toward the junctionof first and second trim elements 10 and 20, in the direction and senseindicated by arrow F. The pressure exerted by airbag 3 on movable part21 of second trim element 20 produces flexion of the said movable part21, permitting it to escape from holding lip 11. Airbag 3 then deploysalong the side of the motor vehicle.

In another practical example, not illustrated, guide surface 12 is anelement of the support of airbag 3, such as, for example, a part of therigid envelope of airbag 3 or an external part having a supportfunction.

In another practical example, not illustrated, guide surface 12 is abody element, such as, for example, a deep-drawn structure made from apiece of sheet metal.

In another practical example, not illustrated, guide surface 12 is anelement made independently of the trim or body.

In these last three practical examples, guide surface 12 can beprolonged as a fixation tab of a trim element while cooperating with,for example, an aperture made in the said trim element.

The trim elements, or at least first trim element 10, can be asheet-metal element of the body.

1. A device for assisting deployment of an airbag, located at a junctionof at least two trim elements of parts of a body of a motor vehicle,wherein a first of the two trim elements is fixed and a second of thetwo trim elements is configured to be deformed under pressure exerted bythe airbag during its deployment, the device including a guide surfaceoriented from an exit zone of the airbag toward an end part of thesecond trim element, wherein the end part, which abuts against the guidesurface, is located at an external limit of a zone of cooperationbetween the first and second trim elements, and wherein the guidesurface is a part of one of the two trim elements.
 2. A device forassisting deployment according to claim 1, wherein the guide surface isa support element of the airbag.
 3. A device for assisting deploymentaccording to claim 1, wherein the guide surface is part of a bodyelement.
 4. A device for assisting deployment of an airbag, located at ajunction of at least two trim elements of parts of a body of a motorvehicle, wherein a first of the two trim elements is fixed and a secondof the two trim elements is configured to be deformed under pressureexerted by the airbag during its deployment, the device including aguide surface oriented from an exit zone of the airbag toward an endpart of the second trim element, wherein the end part, which abutsagainst the guide surface, is located at an external limit of a zone ofcooperation between the first and second trim elements, and wherein thejunction of the guide surface with the trim element forms a lip forholding the first and second trim elements in closed position relativeto one another.
 5. A device for assisting deployment of an airbag,located at a junction of at least two trim elements of parts of a bodyof a motor vehicle, wherein a first of the two trim elements is fixedand a second of the two trim elements is configured to be deformed underpressure exerted by the airbag during its deployment, the deviceincluding a guide surface oriented from an exit zone of the airbagtoward an end part of the second trim element, wherein the end part,which abuts against the guide surface, is located at an external limitof a zone of cooperation between the first and second trim elements, andwherein the guide surface carries an element for fixation of the firsttrim element.